On Tuesday, October 25, a bright flash lit up the sky near Lake Baikal in Siberia, Russia.

The mysterious flying object has left many scratching their heads over what exactly it is. At first, people thought it was the ICBM RS-18 intercontinental ballistic missile launched by Vladamir Putin’s military in Orenburg, but that missile testing would have been seen much earlier in the day.

Some experts believe it is a man-made object, while others think it is a bolide, which is a large meteor that explodes in the atmosphere before it touches the ground. Either way, it must have been an incredible (and unsettling) sight for those who witnessed it.